Help! Carrera has a miss

Jim Smolka · 07-09-2003, 07:47 AM

Ok, I am going nuts.

On the 85 Targa, the car has a miss. From 2500-3500, I can feel a slight miss. Then from about 3500-5000 it pulls great. Then from 5000-6000, the miss is very bad, one if not 2 cyl missing.

Things done so far.

Plugs, wires, cap, rotor, cleaned up the dizzy. Adj vavles when I replaced the clutch.

Check fuel pressure, swapped injectors from race car, ran BG-44k. Cleaned gas tank screen & replaced fuel filter

Swapped DME unit & DME relay.

About the only thing left is the flywheel sensors???

Anymore suggestions???

Thanks in advance

bell · bell's Garage

check your 02 sensor......when they start going bad they can cause similar problems.

Jim Smolka · 07-09-2003, 08:04 AM

Bell,

Thanks, I removed the O2 sensor wires. A quick trip around the block... I still have a miss above 5000 RPMS. Almost like the rev limter in the DME is shutting off the fuel.

Otto · 07-09-2003, 08:08 AM

Tighten down the intake manifolds. Nobody realizes that all 3.2 Carreras need to have the intake manifolds retorqued at every major service. They are always loose. You might also have leaky intake manifold boots. To find an intake leak, start the car and spray STARTING FLUID in the suspect areas that intake leaks might occur. The motor will change its pitch if you have an intake leak.

Jim Smolka · 07-09-2003, 09:17 AM

Thanks Otto.
I plan to run out & pickup some starting fluid.

Also, with the car parked and tranny in neutral, I can hear the miss above 5000 RPMs.

ChrisBennet · ChrisBennet's Garage

Don't be a stranger Otto. We miss you!
-Chris

Jim Smolka · 07-10-2003, 06:49 AM

Ok, I am still going nuts...

I checked all the intake manifold bolts. They were tight.

I swapped the coil, and coil wire. Swapped the air flapper box. Sprayed everything with starting fluid. Checked for vacuum @ the brake booster, good vacuum. Pinched off the vacuum line @ the brake booster, still no improvement. Swapped the tach to make sure it was indicating the correct RPMs.

Any other suggestions.

Otto · 07-10-2003, 10:24 AM

Fuel pressure, pick-up sensors loose or dirty? Plug wire resistance? Proper millivolts generated by the o2 sensor, proper CO? Drive the car here, we will fix it.

Jim Smolka · 07-11-2003, 12:34 PM

Finally, the problem is fixed.

Thanks to all that helped.

Turn out to the the flywheel senors needed to be cleaned and adjusted. Used an old sensors that had an 0.8mm washer glued to the end to set the sensor offset.

Note to self, when replacing the clutch on a Carrera, always remove, clean and adj the flywheel reference senors and flywheel pulse sensor.

Rick Lee · Rick Lee's Garage

Jim, did accessing the flywheel sensor require engine removal? If not, how'd you get to it?

Jim Smolka · 07-11-2003, 03:22 PM

Richard,

The flywheel sensors (2 that are on the same bracket) can be removed with the engine in place. Simply remove the 6mm allen bolt out of the suspect sensor using a 5mm allen socket & wratchet. Then, remove the two 6mm bolts (10mm hex). The sensors and bracket should come out. Wipe and clean the sensors with WD40 and a rag. Carefully push/pry the sensor out. Not too bad of a job

To install;

First find an old sensor and 0.8mm thick washer; glue onto the end. Then insert and secure the old sensor to bottom hole in the bracket. Position and losely secure the bracket to the motor. Position the sensor so that it is touching the ring gear. Tighten the bracket's 2 6mm hex bolts. Remove the old sensor with glued on washer. Install new (or cleaned) sensor.